P3372 【模板】线段树 1

初识懒标记。。。

#include<iostream>
#include<cstdio>

using namespace std;

#define LL long long

const int N = 100010;

struct Node{
    int l, r;
    LL sum;
    LL add; // lazy
}tr[N * 4];

int n, m;
LL w[N];

void update(int u, LL w){
    int len = tr[u].r - tr[u].l + 1;
    tr[u].sum += w * len;
    tr[u].add += w;
}

void pushdown(int u){
    update(u << 1, tr[u].add);
    update(u << 1 | 1, tr[u].add);
    tr[u].add = 0;
}

void pushup(int u){
    tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
}

void build(int u, int l, int r){
    if(l == r) tr[u] = {l, r, w[l]};
    else{
        tr[u] = {l, r};
        int mid = l + r >> 1;
        build(u << 1, l, mid);
        build(u << 1 | 1, mid + 1, r);
        pushup(u);
    }
}

void modify(int u, int x, LL v){
    if(tr[u].l == tr[u].r) tr[u].sum += v;
    else{
        int mid = tr[u].l + tr[u].r >> 1;
        if(x <= mid) modify(u << 1, x, v);
        else modify(u << 1 | 1, x, v);
    }
}

LL query(int u, int l, int r){
    if(l <= tr[u].l && r >= tr[u].r) return tr[u].sum;
    if(tr[u].add) pushdown(u);
    int mid = tr[u].l + tr[u].r >> 1;
    
    LL sum = 0;
    if(l <= mid) sum = query(u << 1, l, r);
    if(r > mid) sum += query(u << 1 | 1, l, r);
    
    return sum;
}

void change(int u, int l, int r, LL v){
    if(tr[u].l == l && tr[u].r == r){
        update(u, v);
        return;
    }
    
    if(tr[u].add) pushdown(u);
    int mid = tr[u].l + tr[u].r >> 1;
    if(r <= mid) change(u << 1, l, r, v);
    else if(l > mid) change(u << 1 | 1, l, r, v);
    else{
        change(u << 1, l, mid, v);
        change(u << 1 | 1, mid + 1, r, v);
    }
    pushup(u);
}



int main(){
    cin >> n >> m;
    
    for(int i = 1; i <= n; i ++) scanf("%lld", &w[i]);
    
    build(1, 1, n);
    
    while(m --){
        int k, x, y;
        cin >> k >> x >> y;
        
        if(k == 1){
            LL v;
            cin >> v;
            change(1, x, y, v);
        }else
            cout << query(1, x, y) << endl;
    }
    
    return 0;
}

P3372 【模板】线段树 1

原文：https://www.cnblogs.com/tomori/p/13762574.html